Rhododendron simsii - double form

Autumn · Outdoors

Apply mulch

Use bark chips or leaf mould to add an organic mulch around the crown of the plant.

A mulch is a covering that can: protect the soil surface from rain, heat and cold; deter weeds; provide nutrients. Organic indicates that material has vegetative origin e.g. manure, compost. Synthetics i.e. plastics, or stones are often called mulches.

Spring-Autumn · Indoors

Feed with houseplant food monthly

Give the plant a balanced houseplant feed monthly while in growth.

Where food elements are listed as three numeric values on the label representing in order Nitrogen(N)-Phosphorus(P)-Potassium(K), with percentage values for each, choose one where the values are more or less equal.

Spring-Autumn · Indoors

Water regularly during growth

Water regularly while in growth.

Adopt a regime that means the plants are thoroughly watered every week so that they do not become dessicated. In hot weather watering may need to be more frequent, but less often in cool or moist conditions.

Spring · Outdoors

Apply acidic mulch

Where soil is only just acidic, apply mulch with a high acidic content such as leaf mould, or mulch for ericaceous plants. Alternatively the plant can benefit from a feed of iron supplement (iron chelate) such as sequestrol.

Spring - late · Outdoors

Feed with slow release fertiliser for ericaceous plants

Apply a slow release fertiliser for ericaceous plants before applying any mulch, spreading it around the root area of the plant as it is coming into growth. (Or apply a liquid feed at regular intervals throughout the growing season.)

This is a simple way to provide a nutrient boost as a single annual procedure.

Spring-Autumn · Outdoors

Water to keep the soil moist

For best results, this plant needs soil that is always moist. Water deeply and regularly as soon as soil appears dry. Even for established plants in the ground, a dry week can cause problems with some soils. Check plants in pots more often, especially in hot weather. Or install an automatic irrigation system which will do the hard work for you, even when you are away on holiday.

Without regular watering some plants never fully regain their beauty.

Winter-Spring · Indoors

Water lightly in winter

The soil should remain just moist during the cold months when the plant is not in growth. Trickle a little water onto the soil surface every couple of weeks if the soil is dry. Do nothing if it is moist.

The roots remain active in winter and benefit from small amounts of moisture so they don't become completely desiccated.

Indoors

Water with rain water

This plant needs rain water or soft water (the minerals in alkaline or "hard" water are harmful). This is especially important for plants in pots.

Outdoors

Water with rain water

This plant needs rain water or soft water (the minerals in alkaline or "hard" water are harmful). This is especially important for plants in pots.

Outdoor planting · Planting

Add root growth stimulant to the planting hole

Mycorrhizal fungi helps roots establish quickly, so they absorb water and nutrients more efficiently. It comes as a powder, granule or gel. Add to the planting hole or container, and to the plant's rootball before planting in the hole. For "bareroot" plants use a gel.

Planting

Deadhead blooms during flowering season

Remove flowers as they turn brown and fade. Snip the stem just below the bloom. This will keep the plant tidy and encourage more flowers.

The removal of spent flowers encourages the plant to produce fresh ones, rather than spend its energy on the development of seeds.

Compost · Planting

Ericaceous compost for repotting

Ericaceous compost is lightweight, so if a light pot is used put heavy crocks in the base, and if the compost dries out, water by standing the pot in water until it has been absorbed.

Some plants require acidic compost to make healthy growth because they are unable to absorb the correct nutrients in soil that contains lime. These plants are called 'calcifuge'. This applies to many rhododendrons, blueberries, and some heathers.

Indoor temperature · Planting

3C minimum temperature

This plant requires a minimum temperature of 3 Centigrade.

Compost · Planting

Ericaceous compost

Plants such as Camellia, Azalea and Rhododendron need acidic (ericaceous) soil. Where the soil is not acidic, or when planting in pots, use an ericaceous compost, or specialist compost for Camellia, Azalea and Rhododendron.

Indoor plant · Planting

Position in indirect light indoors

Give the plant a position that is cool and light, and away from direct sunshine.